Hi there,
I'm getting set up to experiment with using a hi fi circuit (HF60 for starters) that will be using old output transformers from a Leak Stereo 50. They are UL of course and have a primary impedance of 7K. I thought that was unusually high for a pair of EL34's in push pull but, I'm a little bit new to old hi fi tube amp practices.
What differences would you expect to hear if say, one were to hook up an 8 ohm speaker load to the 16 ohm OT tap, especially in terms of volume?
If things work the same with a UL OT as they work with non-UL I would expect the EL34 pair to see something more near 3.5K ohms as a primary impedance - which I have seen that value more typically used in amps than the 7K that the OT's are speced for.
Just to clarify, this stereo amp I'm building up is to be for a musical instrument preamped at line level that possibly may benefit from a more accurate reproduction than say, a guitar type amp - that is to be seen more clearly later on as I experiment with a few things but, I entertain the possibility that since it is an instrument playing only single notes (80Hz and higher) , it may benefit more from a greater volume output than a super low distortion percentage. We will see.
Thanks!
Best,
Phil
I'm getting set up to experiment with using a hi fi circuit (HF60 for starters) that will be using old output transformers from a Leak Stereo 50. They are UL of course and have a primary impedance of 7K. I thought that was unusually high for a pair of EL34's in push pull but, I'm a little bit new to old hi fi tube amp practices.
What differences would you expect to hear if say, one were to hook up an 8 ohm speaker load to the 16 ohm OT tap, especially in terms of volume?
If things work the same with a UL OT as they work with non-UL I would expect the EL34 pair to see something more near 3.5K ohms as a primary impedance - which I have seen that value more typically used in amps than the 7K that the OT's are speced for.
Just to clarify, this stereo amp I'm building up is to be for a musical instrument preamped at line level that possibly may benefit from a more accurate reproduction than say, a guitar type amp - that is to be seen more clearly later on as I experiment with a few things but, I entertain the possibility that since it is an instrument playing only single notes (80Hz and higher) , it may benefit more from a greater volume output than a super low distortion percentage. We will see.
Thanks!
Best,
Phil
The "optimum" load varies as voltage and current varies.
3.4K loading is for guitar amps who want the MOST! watts without going over 450V of DC (avoid costly caps). Hi-fi may prefer a less high-strung approach.
> What differences would you expect to hear if ....
IMHO, bench-racing such comparisons is not a good use of time. Obviously you can move that wire even quicker than you can type the question.
And minor change like this may be "no" difference until pushed to extremes.
3.4K loading is for guitar amps who want the MOST! watts without going over 450V of DC (avoid costly caps). Hi-fi may prefer a less high-strung approach.
> What differences would you expect to hear if ....
IMHO, bench-racing such comparisons is not a good use of time. Obviously you can move that wire even quicker than you can type the question.
And minor change like this may be "no" difference until pushed to extremes.
UL and different taps
Thank you for your comments,
"Optimum load varying with V and I.". I guess that's impedance for you. Don't know how much I can do about that, but this having UL transformers I couldn't wrap my head around if that would make for a differing response electrically in using various other taps. Of course I'll try both but didn't want to assume all will be the same in UL.
All the "little" experiments I'll be conducting on this is to loosely find where a useful range of trade off lies between max volume and distortion. Thats really at the heart of what I'm looking for here. With the old transformers I have available for this right now, I'd like to see if there could be at least enough volume generated to be say, an acceptably loud enough stage monitor with a band in a small room. So far, the set up would be instrument/DI/mic pre/stereo reverb processor/DA into L and R channels of the stereo tube amp. Being as that we like things like reverb to not get too mangled, I have to assume that a bad guitar amp topology may not suit the application so, seeing it there is a balance that will work for this.
Also, its very probable that I will try cathode bias and fixed, see how each plays out. I did originally assume I would go fixed.
Thanks and Best,
Phil
Best and thanks,
Thank you for your comments,
"Optimum load varying with V and I.". I guess that's impedance for you. Don't know how much I can do about that, but this having UL transformers I couldn't wrap my head around if that would make for a differing response electrically in using various other taps. Of course I'll try both but didn't want to assume all will be the same in UL.
All the "little" experiments I'll be conducting on this is to loosely find where a useful range of trade off lies between max volume and distortion. Thats really at the heart of what I'm looking for here. With the old transformers I have available for this right now, I'd like to see if there could be at least enough volume generated to be say, an acceptably loud enough stage monitor with a band in a small room. So far, the set up would be instrument/DI/mic pre/stereo reverb processor/DA into L and R channels of the stereo tube amp. Being as that we like things like reverb to not get too mangled, I have to assume that a bad guitar amp topology may not suit the application so, seeing it there is a balance that will work for this.
Also, its very probable that I will try cathode bias and fixed, see how each plays out. I did originally assume I would go fixed.
Thanks and Best,
Phil
Best and thanks,
What they are suggesting is to write down the voltage the tubes will be working at, and I would say the UL percentage as well.
In any case I'd stick on the 7 kOhm Raa.
Just to saym with 20% UL that's the load you find on datasheets at 450 V B+.
In any case I'd stick on the 7 kOhm Raa.
Just to saym with 20% UL that's the load you find on datasheets at 450 V B+.
Hey Phil,
I believe your Leak Stereo 50 output transformers would be very valuable to someone who wanted to build a Leak clone. Sell them and buy any set of transformers you need/like for your “musical instrument amplifier”.
See what a Leak goes for. Leak Ponte One Stereo 50 Tube Amplifier Use KT66 EL34 6L6 In US Voltage Original | eBay
Good luck.
Leak stereo 50 transformers
I can't deny that I wrestled over many days with the prospect of "not updating/upgrading/maintaining the Leak stereo 50 as the stereo tube amp it was created as". I was pulled equally in 2 ways but, my justification was that I would rather build a stereo tube amp from scratch one day. Other reasons were that as the sole provider in my house with dependents I cant get too greedy with my acquisitions (new transformers) as much as I's surely like. And the instrument that I built deserves an amp system as unique as it is. As painful as it was it occurred to me that the value of things is sometimes where we find it.
Well, whether this justification fall short or wins, I wont be selling off any of the Leak parts and they will be in my hands should I change my mind on anything about it.
Oh yeah, the OT"s have 50% taps. I believe the later Stereo 50's went to a 20% tap.
Thank you and perhaps I will just run the taps as intended, or just do a quick experiment to hear the difference. I just wanted to check if there wasn't anything extenuating to know about differing primary impedances with UL OT's since I've never met with them before.
Best,
Phil
I can't deny that I wrestled over many days with the prospect of "not updating/upgrading/maintaining the Leak stereo 50 as the stereo tube amp it was created as". I was pulled equally in 2 ways but, my justification was that I would rather build a stereo tube amp from scratch one day. Other reasons were that as the sole provider in my house with dependents I cant get too greedy with my acquisitions (new transformers) as much as I's surely like. And the instrument that I built deserves an amp system as unique as it is. As painful as it was it occurred to me that the value of things is sometimes where we find it.
Well, whether this justification fall short or wins, I wont be selling off any of the Leak parts and they will be in my hands should I change my mind on anything about it.
Oh yeah, the OT"s have 50% taps. I believe the later Stereo 50's went to a 20% tap.
Thank you and perhaps I will just run the taps as intended, or just do a quick experiment to hear the difference. I just wanted to check if there wasn't anything extenuating to know about differing primary impedances with UL OT's since I've never met with them before.
Best,
Phil
the magical single note only instrument
dgta, That's a great response, man could the world have a field day with that one, on a technical, meta-physical and artistic plane.
OK, you gat me, it has 6 strings so yes, you definitely can get more than one note at a time out of it. I just have no interest in doing that whatsoever because I built the thing with only an EBow in mind, and the Ebow will only get you one note at a time. (pretty much)
I don't like the sound of fretless guitars very much, and don't have much confidence in my abilities to excel on one should I attempt to.
But, its very feasible to get one note at a time using an Ebow, while having some of the expression elements of a true stringed and bowed instrument such as liquidous vibratos where you can place the apex of the vibrato anywhere around the note, and you have portamento and grace noting the same way as a string instrument that is difficult to render from a standard guitar (which is my main instrument). I'm really just a local classic rock guy that has been secretly jealous of string players lyrical expression abilities, and although this instrument is severely limited in comparison to a real stringed instrument, It exceeded my expectations when I finally strung it up and played it. Here is a link to a soundcloud clip I made. This clip is my first experiment with granular synthesis and I also played some "Ebow guitar" starting at 2:30.
]SoundCloud - Hear the world’s sounds
I'm Only One Person by Philster | Free Listening on SoundCloud[/url]
Its a strange, odd and quirky instrument and I expect as many people to hate it as they do like it but, I'm having a good time with it and want to make a good presentation for it in terms of live sound. To me, that means a really nice and well thought out monitoring system that can be miced up in stereo a bigger gigs or venues.
I don't expect to win an trophies for this, just bring up something a little unique and fun.
Best and thanks - this a very interesting forum with lots of perspectives and expertise - its worth getting my butt kicked now and then,
Phil
Phil
dgta, That's a great response, man could the world have a field day with that one, on a technical, meta-physical and artistic plane.
OK, you gat me, it has 6 strings so yes, you definitely can get more than one note at a time out of it. I just have no interest in doing that whatsoever because I built the thing with only an EBow in mind, and the Ebow will only get you one note at a time. (pretty much)
I don't like the sound of fretless guitars very much, and don't have much confidence in my abilities to excel on one should I attempt to.
But, its very feasible to get one note at a time using an Ebow, while having some of the expression elements of a true stringed and bowed instrument such as liquidous vibratos where you can place the apex of the vibrato anywhere around the note, and you have portamento and grace noting the same way as a string instrument that is difficult to render from a standard guitar (which is my main instrument). I'm really just a local classic rock guy that has been secretly jealous of string players lyrical expression abilities, and although this instrument is severely limited in comparison to a real stringed instrument, It exceeded my expectations when I finally strung it up and played it. Here is a link to a soundcloud clip I made. This clip is my first experiment with granular synthesis and I also played some "Ebow guitar" starting at 2:30.
]SoundCloud - Hear the world’s sounds
I'm Only One Person by Philster | Free Listening on SoundCloud[/url]
Its a strange, odd and quirky instrument and I expect as many people to hate it as they do like it but, I'm having a good time with it and want to make a good presentation for it in terms of live sound. To me, that means a really nice and well thought out monitoring system that can be miced up in stereo a bigger gigs or venues.
I don't expect to win an trophies for this, just bring up something a little unique and fun.
Best and thanks - this a very interesting forum with lots of perspectives and expertise - its worth getting my butt kicked now and then,
Phil
Phil
what dgta wanted to say is that musical instruments give a complex harmonic content at their output for each note you play. Often the 1st harmonic is not even the strongest one.
harmonics
Ah, Ok,
I missed that!
In that case I am in complete agreement with dgta (sometimes I wish those harmonics would subside a little at 8.5Kh, but, working on it.
Thanks, and best,
Phil
Ah, Ok,
I missed that!
In that case I am in complete agreement with dgta (sometimes I wish those harmonics would subside a little at 8.5Kh, but, working on it.
Thanks, and best,
Phil
No. What I mean is that I know of no instrument INCAPABLE of playing more than one note at a time. Such an instrument would have to prevent you from playing the second note before the decay from the first note has completely gone to zero.
My wife is an instrument that can holler more than one line at a time.
But she's very special.
I'll get a soundclip of her yelling and put some delay and reverb on it. Then we'll hear some notes beginning before the previous one ends - will prove your last theory with no reasonable doubt.
But she's very special.
I'll get a soundclip of her yelling and put some delay and reverb on it. Then we'll hear some notes beginning before the previous one ends - will prove your last theory with no reasonable doubt.
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It's feasible to get one note at a time from ANY instrument. Not clear what one note at a time has to do with the design of any amp, perhaps you can explain how that's an issue.
I don't know what this means. You won't get two notes at a time out of a flute or many other woodwind instruments, and the 'decay' if any will be actively interfered with by the production of the second note.
Exactly. At the instant you start the second note, the instrument is producing the second note and still emitting the tail end of the first note. Call it two notes at once, call it intermodulation, call it interference or anything else you like. It's not a single frequency. This is not just a trivial detail, the decay characteristic has a lot to do with the "sound" of various instruments.
You could design an electronic instrument that abruptly cuts off the first note decay before the second note starts, but it would sound weird.
My wife can accidentally do DTMF tones and send herself straight to voicemail instead of some other phone system path.🙂
one note
Here is one of the things that probably inspired me to highlight the "one note at at a timeness".
As I've looked at replacement transformers such as the Dynaco's, I've noted that the output power will be specified like this:
35 watts - 20-20,000 Hz.
70 watts - 30-15,000 Hz.
Perhaps I'm wrong but, this set the notion that should the system be only introduced to material that is single noted "not as complex" and does not require producing frequencies below 80 Hz "Far less risk of transformer saturation and far less heat/work trying to translate looong high energy low frequency wavelengths", that the system and presumably the transformers could manage to generate a greater volume for "single noted things not below 80Hz."
Over the course of implementing this stereo amp I will be interested in garnering as much volume as possible while retaining good fidelity for the instrument - and I don't believe its possible to know what that is until some experimenting with various things like NFB and impedance are experimented with.
What's ya think?
thank you and best,
Phil Donovan
Here is one of the things that probably inspired me to highlight the "one note at at a timeness".
As I've looked at replacement transformers such as the Dynaco's, I've noted that the output power will be specified like this:
35 watts - 20-20,000 Hz.
70 watts - 30-15,000 Hz.
Perhaps I'm wrong but, this set the notion that should the system be only introduced to material that is single noted "not as complex" and does not require producing frequencies below 80 Hz "Far less risk of transformer saturation and far less heat/work trying to translate looong high energy low frequency wavelengths", that the system and presumably the transformers could manage to generate a greater volume for "single noted things not below 80Hz."
Over the course of implementing this stereo amp I will be interested in garnering as much volume as possible while retaining good fidelity for the instrument - and I don't believe its possible to know what that is until some experimenting with various things like NFB and impedance are experimented with.
What's ya think?
thank you and best,
Phil Donovan
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No, I believe the "single note" notion is misplaced here, but I wouldn't worry about it. If you have an amp capable of full power at 30Hz, there aren't many instruments that need to go lower than that and certainly not at full power. Unless you have some odd requirements you didn't state.